Sheet transporting and stacking device for printing machines



Nov. 6, 1956 w. KOCH SHEET TRANSPORTING AND STACKING DEVICE FOR PRINTING MACHINES 2 Sheets-Sheet 1 Filed Jan. 30, 1953 &

. Inventor": A/ik -/VR KUCH 3 M Arron/Ir Nov. 6, 1956- 2,769,634

' W. KOCH SHEET TRANSPORTING AND STACKING DEVICE FOR PRINTING MACHINES Filed Jan. 30, 1953 2 Sheets-Sheet 2 jm emon A/ER IVER Koch United States SHEET TRANSPORTIN'G AND STACKING DEVICE FORPRINTING MACHINES Wemerr Koch;v Oifenbach (Main), Germany, assignor' to Faber: &.' Schleicher' Aktiengesellschaft, Ofienbach (Main), Germany, a body corporate of Germany Application January 36, 1953, Serial No. 334,292 Claims priority, application Germany February'6, 1952' 7 Claims. (Cl. 271-79) This. invention relates to machines for working on sheets such as printing machines for example, and in its more particular aspect refers to the sheet transporting and. stacking devices for such machines of the kind in which the sheets on their way to the delivery stack are slowed down so as tooverlap each other while being thus conveyed.

A type of device at present in use comprises two chain grippers traveling. at constant, but mutually varying speeds. The sheets are transferred by the grippers on the quicker chain to the grippers of the slower chain to be conveyed to and deposited on the stacking table. Thechain grippers, in these known devices are positioned on both sides. of the track of the sheets, but the difference in the speed. of the chains is limited by the transportation means of the quicker chain tending to damage the ends of.v the preceding sheets, so that these devices do not meetthe'requirements. of modern printing machines.

Other devices. are known in which the chain which conveys the sheets outwardly is slowedv down by means ofa gear. In this case the sheets can be deposited only at appreciable. intervals from each other and, again, the conveying means are provided atboth sides of the trackof the. sheets as in the case just referred to. Another. disadvantage of this type of devices rests in that the sheets. are conveyed. irregularly. There may be only one ata time, or a number of them appearing simultaneously, whichrenders overlapping an impossibility.

In stacking devices for overlapped feeding slowly moving conveyers are generally used. The sheets are positionedonto the slowly circulating conveyers by meansof grippers by means. of which they-are then transported tothe stack. Devices of this kind cannot beused for large sized sheets or. for thin paper.

All these. andother known devices. are either limited in their application: or they are technically too complicatedto be of practical use. In many cases they are unreliable, while in others they. are. capable of achieving only apart of the. results which they are called upon to perform. It is, therefore, the principal object. of this invention to remove all these and. other shortcomings and to provide sheet transporting and stackingdevices of the kind herein referred to, which are simple. in. construction and which will reliably handle all sizes and thicknesses. of any such materials as may come into question.v

With. this andv other objects. in view the. invention mainly consists in an improved. device. of the type first herein referred to, in which two conveyers or the like are provided, which. travel at different speeds and. Which are adapted to carry gripper systems, or other. sheet supporting means, which. are arranged both. at the same side of the. track of the sheets.

The invention, further, provides for a deceleration of the sheets. on theirway to. the. stack sufiiciently as to permit of their overlappingwhile they are being. conveyed. This objectis attained mainly by the employment of two chains or the like which are moved at F'atented Now 6,- 1-956 different but constant speeds, and' in which: the; slower of the two'chains is adapted to reciprocate, OHOF within special guide tracks, a plurality of gripper carriages having connecting rods by means of which they are attachedto the'said chain. Shortly before theendofnthe outward travel thesheet is. deposited. onto the stack. at a traveling speed of the carriage. which: is; practically zero.

At their turning points the chainsi which are; used for the-conveyance ofthe. sheets are passed over; chain wheels or. sprockets, and. in' accordance with the: invention the number of teeth: of these: sprockets is; preferably larger than the'number of links between :each two suspene sion points: for the sheet supporting devices in order therebyto' maintain the forces: of acceleration: and: dc;- celeration in moderate limits. In somecases itmay 'be necessary, OI'i practical,,tot make the number of teeth equal to a multiple of the number of links; of the. various systems. in order to be. able to-fix cams to the chain wheels or sprockets for controlling the movement of the sheet supportingimeansin accordance with the work ingcycle of the-machine..

In accordance with-the invention the guide tracksand the chain which is working in conjunction .therewithare so movingin relation. to each other; that th'e'connecting rods between the chain and the: sheet supportingrmeans undergo. a fr'equentchange intheir traction angle, so as: to'moveitheisaidsheet supporting means atfirstwith approximately the" speed of the delivery chairr,. and. to then transport them at continually decreasing." speed to the; turning. pointabovethe stack, while all: the time the chain continues its movement atxconstant speed; At both endsof the trackthe sheetsupportingimeans are reversed by being'ledcover. switches into: another track, or; another branch ofth'etrack respectively, whereby the position of the said switches isbeing controlledpreferably by suit able. cams or eccentrics adjacent the. ends. of the said tracks and, preferably, fixeditoithe chain wheelsati these ends. a

The accompanying drawing. diagrammatically. illustrates' an arrangement in. accordance. witlrthe invention .by way of example.

Fig. 1 is a side-view, partly in section, of the sheet transporting and stacking device, and

Fig. 2 is.'a.motion diagram illustratingithe development ofv the movement of the conveyer chain at. the receiving end of'th'e device:

In accordance with this embodiment of the invention the transportingv and stacking device comprises a chain 1 which. is' caused by any known or convenient means, preferably in: connection with. theprinting or other machine to which. the invention appertains, to travel in a direction indicated by the arrows over chain wheels, or sprockets, 2, 3; and 4; and ata constant but slower speed thanthat.of..the.delivery"means of the machine. Connecting rods 5' are linked up to the chain at spaced intervals, which: are in' connection with small carriages 6 capable: of traveling: fore and back. in' guide: tracks 7 and 8: respectively. These guide tracks are of mutually different curvature; the path whichthey' cover deviates from the path of the chain 1. The tracks approach each other at their'ends at a sharpangle', and as the carriages have to be reversed in their direction oftravel and to be changed over'fronr the advancing track 7 into the returning track 8, and vice'versa, change-over switches are provided to allow ofsuchtransfer; At the starting end a switch 9 is provided which is controlled from a cam 10 by means of a lever ll'so. as to permit'of' the reversal of the carriages 6' from the returntrack'8 into the for- 12-is' provided. which is controlled in a similar'manner by a cam 13 which is in fixed relation with the chain wheel 3, and which controls the switch 12 by means of a f cam follower, link-s 14and a lever 15. Fastened to the carriages 6 are gripper bars'16 having grippers 17, which receive the sheets 19 from the grippers 18 of the delivery chain 22 of the printing machine in substantially known manner and convey them to be deposited onto the stack 19. V

The sheets 19 which are delivered from the printing mechanism by the grippers 18 on the delivery chain 22 are taken over at the place where they leave the delivery end of the machine, by the grippers 17 which are carried on the gripper bars 16. At this moment the speed of the carriages 6, to which the gripper bars are attached, is accelerated to the speed of the delivery chain. This is owing to the connection point 21 at which each connecting rod is linked to the chain 1 beginning to approach the guide track 7. Hereupon the movement of the carriage begins to slow down at an increasing rate owing to the path of the chain deviating from the track 7 with the result of the sheets 19 overlapping each other.

While the guide track 7 takes its direction approximately parallel to the top edge of the stack 19', the chain 1 proceeds at a moderate upward inclination. When the pivot 21 of the connecting rod 5 moves over the lower part of the chain wheel 3, the speed of the carriage 6 drops to almost zero. At about this moment the carriage is pushed into the portion of the track in the switch 12 and the sheet is liberated to drop down onto the stack 19'. As soon as the carriage 6 has arrived in the switch 12, the said switch is turned upwardly by means controlled by the cam 13 comprising links 14 and a lever 15, whereby the track portion in the switch will be connected up to the track 8, and the carriage 6 will now be able to enter this track, being drawn into it by the constantly moving chain 1 and the connecting rod 5. The carriage travels now in the reverse direction along the track 8 until itagain reaches the starting switch 9. When the link 21 of the rod'S passes over the chain wheel 2, the speed of the carriage 6 is again slowed down to approximately zero. During this time the cam is actuated to turn the switch 9 by the lever 11 into communication with track 7, into which the carriage can now enter, whereupon the operation is repeated as before.

Referring to Fig. 2 in which the development of the movement of the carriage 6 at the lower switch 9 is encase l chain receiving the sheets from the gripper means of the first chain in a predetermined transfer position, a first guide track guiding the sheet carrying gripper means of the second chain over the top of said delivery stack,

means releasing the sheet from the gripper means of the second chain when above the delivery stack thereby depositing sucessive sheets thereon,.a second guide track returning the gripper means of the second chain into said transfer position, the ends of said guide tracks joining at a sharp angle at which the gripper means reverse their travel, and a change-over switch at each of the joined ends of said guide tracks guiding the gripper means of the second chain from. one track into the other, said change-over switches being controlled in their movement fromthe mechanism of the printing machine.

2. in a printing machine for printing sheets, a device, including a first chain and grippers on said chain, traveling at the speed of the printing mechanism for conveying the sheets as they are delivered from the said printing mechanism, a second chain and grippers for gripping the sheets from said first chain grippers andgtransporting them to a delivery stack, two tracks,'one for the conveyance of a gripper of the second chain carrying a sheet. to the delivery stack and the other for returning the gripper without a sheet, said tracks joining at both their ends whereat the gripper reverses its travel, a change-over switch at each end of said tracks for transferring the gripper from one track to the other, said second chain traveling at a constant but lower speed than the first chain, means for releasing the sheets from the grippers of the said second chain above the stack, and means for explained, chain 1 travels at constant speed over the a chain wheel 2, whereby the carriage 6 passes through the distance a on the guide track 8 when the link 21 has moved a distance corresponding to the rotation of the wheel 2 through an angle of 15.". After the carriage has entered the lower guide track 7 via the switch 9 as already referred .to, it'passes through the distance b when the link 21 .hasmovedfrom c to d, corresponding to an angular movement of the wheel 2 through again 15. It will be seen that the distance b isconsiderably greater than the distance a, and it is advisable to keep the distance b during the transfer of the sheets of the same, or approximately the same, length as that through which the grippers 18 on chain 22 travel in the same interval of time. The figure also shows that along the succeeding points of the chain 1, as marked in its curved path, the distances throughwhich the carriage 6 passes on track 8 are greater than those. of the respective distances passed through by the chain 1. What Ivclaim is: V

1. In a printing machine for printing sheets, a device for transporting the sheets from a printing'mechanism to a delivery stack at a decreasing rate of travel to eifect overlap of the sheets while in transport, said device comprising a first chain for delivering sheets from said printing mechanism, a second chain for depositing sheets on said stack, drive means for driving the'firs t. chain at a higher rate of speed than the second chain, spaced apart gripper'means on each chain releasablygripping the sheets, in'transport, the gripper means of said second actuating the change-over switches at the joined ends of. the tracks so as to permit the transfer of the grippers of the second chain from one track into the other.

3. In a printing machine for printing sheets, a device including a first chain and grippers on said chain, traveling at a constant rate of speed in conformity with the printing mechanism of the machine, for conveying the sheets as they are delivered from the said printing mechanism, a second-chain and grippers for gripping the sheets from said first chain grippers at a predetermined transfer position and transporting them to a delivery stack, two mutually superposed curved tracks, one for the movement of a gripper of the second chain carrying a sheet to above the delivery stack and the other, of a different curvature, for consecutively returning the gripper Without a sheet to the said transfer position, said tracks joining at a sharp angle at both their ends, a change-over switch at each end of said tracks for transferring the gripper from one track to the other, said second chain traveling at a lower rate of speed than the first chain to effect overlapping of the sheets while in transport, means above the said stack for releasing the sheetsfrom the grippersof the second chain, and mechanically driven means for controlling said change-over switches in timed relation to the delivery of the sheets from the printing mechanism so as to enable the transfer of the said grippers from one track into the other. j V

4. The sheet transporting and stacking device for use in sheet printing machines as set forth in claim. .1, in which the changeover-switches at both adjo ining ends of said tracks are controlled by cam means from the drive ofthe printing mechanism in synchronism with. the travel of. the gripper means of the second chain so as to switch over from the track in which the gripper means has just completed its trayelinto the adjoining track for continuing its travel in the reverse direction.

stack, comprising, a first chain and grippers on said first chain for conveying the sheets from the printing mechanism, a second chain comprising gripper means for receiving the sheets at a predetermined.transferrposition from the grippers of the first chain, conveyingthem to the delivery stack and, after depositing them thereon, returning to the said transfer position, chain wheels at both ends of the said second chain for driving said second chain at a constant but lower speed than the first chain to enable the sheets to overlap, a curved guide track leading from the transfer position for guiding said gripper means to the sheet delivering position above the delivery stack, another guide track of a different curvature for returning the gripping means to said transfer position and having its ends joining the ends of the firstnamed guide track at a sharp angle, a plurality of carriages arranged for movement in said guide tracks, said gripper means being mounted in said carriages, connecting rods linking each of the said carriages at spaced intervals to the said second chain, a change-over switch at each of the adjoining ends of said guide tracks, and mechanical means for moving said change-over switches in timed relation to the travel of the gripper carriages, each of the said chain Wheels being so positioned in relation to its adjacent switch that each connecting rod moves with its connecting pin on the chain around a part of the said chain Wheel while its respective carriage temporarily remains in the switch so that the speed of the carriage at the reversing ends of its travel practically comes to zero but is accelerated again after the traveling direction of the carriage has been reversed.

6. The sheet transporting and stacking device for use in sheet printing machines as set forth in claim 5, in which the change-over switches at both adjoining ends of said tracks are controlled by cam means from the drive of the printing machine in synchronism with the travel of the gripper carriages so that at the sheet receiving end of the tracks each gripper carriage on the second chain assumes approximately the same speed as the sheet conveying grippers of the first chain.

7. In a printing machine for printing sheets, a device for transporting the sheets from the printing mechanism to a stacking device having a stack table at a decreasing rate of travel to eiiect overlap of the sheets while in transport, said device comprising, a chain and gripping means on said chain for delivering the sheets from the printing mechanism, another chain also having gripping means for receiving the sheets from the gripping means of the first-named chain at a predetermined transfer position and transporting them at a gradually decreasing speed to'the stack table, a curved track for guiding said gripping means of the second-named chain to the stack table, another but differently curved track for returning the gripping means of the second chain to the said transfer position, said tracks joining at both ends at a sharp angle whereat the gripping means reverse their travel, a change-over switch at each of the adjoining ends of the tracks to enable the transfer of the said gripping means from one track to the other, and means for changing over the said switches operating in timed relation to the travel of the said gripping means when the latter reverse their travel.

Relierences Cited in the file of this patent UNITED STATES PATENTS 2,610,850 Huck Sept. 16, 1952 30 2,639,664 Albrecht May 26, 1953 FOREIGN PATENTS 503,032 Germany Oct. 16, 1927 513,206 Great Britain Oct. 6, 1939 

